Slide rule



Jan. 5 1926.

R. SCHWANDA SLIDE RULE Filed August 26. 1921 .lttorney Patented Jan. 5, 1926.

UNITED STATES PATENT OFFICE.

RICHARD SCfiWANDA, OI HOTTING-INNBIBBUCK, AUSTRIA.

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Application filed August 80, 1821.

slide rules heretofore known are generally the groove is formed, of several arts which are combined so as to reliably an accurateclly guide the slide and the index. Such s11 e valves can at present only be produced at very high prlces on account of the accuracy I required and the nature of the material used.

The consequence is that many people who ought to use a slide rule are unable to do so.

The object of mv invention is to-prov1de a slide rule which can be manufactured cheaply but at the same time is very accurate.

In the drawings aflixed to this specification and forming part thereof, I have illustrated several modifications of my invention.

Fig. 1 is an elevation and Fig. 2 a cross section of one modification,

Figs. 3 to 7 are cross-sections of other modifications.

Fig. 8 is a view similar to Figure 1 of Fi Figs. 9 to 12 are cross sections of a slide rule having several scales on the slide.

Fig. 13 is a view similar to Figure 1 of Fig. 12.

,The slide rule illustrated in Figs. 1 and 2 consists of a U-shaped body R. The body 1s formed from a strip of thin material which can be bent and at the same time possesses a certain stifi'ness, such as sheet metal. The strip is doubled up until both its lateral parts a and b are nearly in contact w1th each other along their edges. While bending a strip, the bottom of the U-shaped part 1s extended to form a sleeve H. The slide Z is a strip, the length of which is equal to that of the U-shaped body and which is made of the same material as the U-shaped My invention relates to sliderules. The

amount of material use Serial I0. 485,701.

body or another material, and provided at both ends with beads W. The beads are of somewhat smaller diameter than the sleeve H of the bodv B so that they can freely move in it, while the edges of the lateral parts a and b resiliently engage the flat portion of the slide.

The lateral parts a and b of the U-shaped body and both sides of the slide are provided with scales which co-o erate. These scales may be printed, etche etc. in any manner made of wood, card board and the like and convenient for quantity reduction. Asthe d for the slide is in proportion to its length. in the present modification, in order to obtain the greatest accuracy with the smallest amount of material possible, only simple scales marked with the nurn'erals 1 to zero are provided on the lateral parts a and b of the U-shaped body, while the same scales, but in reclprocal arirangement, are provided on the slide. The slide rule is used in the known manner. the

two factors being placed over each other and the result is read at a mark. Owing to this arrangement of the scales, a slide rule which is only five inches long has the same accuracy as a slide valve of the ordinary type which is ten inches long. The number of scales which cooperate in the present arrangement, is 2. Obviously, any number of scales may be provided if the slide Z and the lateral parts a, b are made wider.

In order to be able to read a scale which is concealed by the lateral parts a, 6, these parts are provided with openings S, which, if desired, may be provided with an index M. It is also possible to lace U-sha ed bodies like R on both beads WV of the side Z, which increases the number of scales to 4. Both U-shaped bodies may be adapted to be adjusted independently or combined into a rigid frame. In order to mark a divisional line on a scale, indexes L L on tubes pro-' vided with glass vanes on which marks are etched, are provided to slide on sleeve H on the U-shaped body B.

This slide rule canbe manufactured by the most simple operations and entirely mechanically by quantity production and at the same time with the greatest accuracy, so that the object of my invention is obtained with the smallest expense possible.

When using a material which is not suflicientl stifi or stronger cannot be formed readi y into the desired shape, the bottom of the U-shaped body must either be strengthened by thicker material of suitable shape or made entirely of such material. 10

the sleeve H of the U-sha d body is strengthened b 2 slotted tn 1 and 2 of sheet metal. 'Iiibe 1 is placed into and tube 2 over the sleeve H the shape of the tubes being such that on the one hand they firmly enga the material between them, while on the other hand the lateral parts 0, b of the U-shaped body are in such posltion that their edges engage the slide Z with resilient The beads W of slide Z may be formed by U-shaped strips of plate 3, as in F1 4, which are placed over the edges of the s de. These strips may be formed to a cylmdrlcal sleeve W, see bottom of Fig. 5, or only bent to such an extent as is necessary for guiding the slide in the sleeve H, see W, top of In, Fig. 6 a modification is illustrated in which the bottom of the U-shaped body is entirely made of stronger material than the lateral arts, in the present case of a strip of wood havin a groove 5, in which the bead 8 of slide is ided. The cross section of strip 4 is suc that the edges of the lateral parts a and b which are attached to the faces 6 and 7 of the strip 4, engage slide Z under resilient pressure, while t e strip 4 makes a guide for the index L sliding on it. The beads of the slide Z are here for use by semicylindrical strips 8 of wood. Two suc strips are attached to either side of the slide forming beads of circular cross section which are guided in the groove 5 of the strip 4.

In Fig. 7 a modification is illustrated in which the bottom of the U-shaped body R consists of a strip of wood 9 without a special uiding groove for the slide Z. The slide as no heads, but with its edge en ages the bottom of the U-shaped body R. n order to prevent the slide lifting from the bottom of the U-shaped body, the index L for marking the divisional lines of the scale, which is guided on the strip 9 is so formed, that it encloses the body R as well as the slide Z at the same time, permitting lateral dis lacement of the slide in the U-sha ed bo y but holding down the slide on the ottom of the U-shaped body.

In all the modifications illustrated a certain inaccuracy or parallaxis occurs when the lines of the scales are not viewed at right angles, because the scales on the slide and the lateral parts are at a distance from each In the modification illustrated in Fi 8" other equal to the thickness of the plate or other material.

With ve thin material and for ordina purposes, t is inaccuracy may be neglect whereas it is unconvenient with greater thickness of material and when very exact readin are necessary.

In igs. 9 to 12 modifications are illus irated in which this drawback is removed. In both cases, strips S, S or S, S, respectively, provided with scales are fixed on the slide Z, the edges of which abut a ainst the edges of the lateral parts a, b. I the scale stri s and lateral arts a b are of the same thic ness, the scaes will be in the same plane.

In the modification illustrated in Fig. 11, the slide Z is grovided with two scale stri S, S and S, 1 at the top and bottom. tween the two pairs of strips there is an open space C where the two lateral parts en the slide. By reversing the position 02%: slide, it is possible to operate with 6 difierent scales.

The modification illustrated in Figs. 10 to 13 has only two scales S, S on the slide Z. It is similar to that illustrated in Figs. 7 and 8. The U-shaped body R and the index L are shown in Figs. 10 and 11 se aratel The slide cannot be reversed here. It is he d in the manner described b a loop shaged index L and the part of t e slide whic is in the U-shaped body R only serves for guid- I wish it to be understood that I do not desire to be limited to the exact details of construction shown and described, for obvious modifications will occur to a person skilled in the art.

I claim:

1. A slide rule comprising in combination, two flat slidably engaged slides of substantially equal length, one slide being U- shaped in section and embracing one lon tudinal edge and the adjacent portion of t e faces of the other slide.

2. A slide rule comprising in combination, two flat slidably engaged slides of substantially ual length, but of unequal width. the outer side being 'U-shaped in section and embracing one longitudinal edge and the adjiicaent portions ofi the faces of the other s 1 e.

3. A slide rule comprisin in combination, two flat slidably engaged s ides of substantially equal length, one slide being U-shaped in section and embracing one longitudinal edge and the adjacent portions of the faces of the other slide, the side portions of said U-shaped slide converging towards one another.

4. A slide rule comprising in combination, two flat slidably engaged slides of substantially equal length, one slide being U- shaped in section and embracing one longitudinal edge and the adjacent portions of the faces of the other slide with elastic pressure.

5. A slide rule comprisin in combination, two flat slidably engaged s ides of substantially equal length, one slide being U- shaped in section and embracing one longitudmal edge and the adjacent portions of the faces of the other slide, a split tube surrcundinithe whole of the curved ortion of 10 said U- aped slide and another ongitudinally split tube inserted in said curved portion.

In testimony whereof I afiix my signature.

ING. RICHARD SCHWANDA. 

